Columbia River pilots say longshore protesters surrounded their vehicle at a Vancouver picket line Wednesday, slapping car windows and yelling personal threats against the pilots and their family members.

The five pilots, arriving by car at United Grain Corp. to dock a ship, were blocked for almost 20 minutes by a group of about 10 picketers who shouted their names, took photos and videos and rattled car door handles, said Capt. Paul Amos, president of the Columbia River Pilots Association.

"They said they were going to harm my family, they were going to harm my career," said Capt. Anne McIntyre, vice president of the association, who was driving. "They said stuff like, 'Scab. We know where you live. Think about your family. We can make your life hell. Everything will be fine if you turn around.'"

The incident, captured on video, is the most confrontational since Feb. 27, when United Grain locked out longshore workers, accusing a union officer of sabotaging equipment. It involves river pilots, who are required by law to maneuver ships in and out of terminals and up and down the Columbia shipping channel.

The pilots, licensed by the state of Oregon, are neutral parties to the dispute. But their role draws attention during lockouts and strikes, when they must cross picket lines to maneuver ships through the channel.

The incident is reminiscent of conflicts two decades ago between longshoremen and river pilots during labor disputes at Peavey Co., a Washington company that tried to exclude the union. Back then, a couple of pilots split from their association to service ships and keep Peavey's corn and soybeans moving.

Ultimately longshoremen signed a contract with Peavey under less favorable conditions than those at other export terminals. That precedent undermined the union's position during contract talks with other Northwest grain terminals over the years. It continues to bedevil longshoremen in their current dispute with United Grain, Columbia Grain Inc. and Louis Dreyfus Commodities.

Until this week, however, United Grain picket lines appeared orderly, despite emotions that have run high since Northwest grain-terminal contracts expired Sept. 30. But river pilots said tensions increased this week as union members drove through the Pilots Association parking lot in North Portland, photographing cars and people coming and going from the office.

McIntyre said she spoke by phone Wednesday to the president of ILWU Local 4, explaining that her team needed access to bring a waiting ship to United Grain's dock for loading. She drove a pilots association Ford Taurus, with four other pilots as passengers to provide support.

At the terminal gate, picketers forced the car to a stop and began circling it, she said. Picketers held some kind of listening device with a plexiglass cone to the rear right window, she said.

A picketer pointed out a wedding ring worn by one of the four male pilots. "I see you're married. Think about your wife," the picketer said, according to McIntyre. She said that another picketer told her, "Don't move this car, you might hit me."

A terminal worker said police officers had been called, but none showed up. McIntyre inched the car through the gate.

The pilots rode a non-union tugboat hired by the grain companies to the Bulk Uruguay, a 57,900-ton vessel at anchor. As the pilots got the Panama-flagged ship underway, three protest boats showed up. Picketers aboard the boats yelled threats and insults through a bullhorn, McIntyre said. But they respected a U.S. Coast Guard safety buffer zone.

Non-union workers secured the ship to the dock. But despite the lockout, longshore workers from another local secured the stern, because it extended beyond the terminal to Port of Vancouver property.

The pilots called for a police escort to cross the picket line and leave the terminal. An hour later, four police cars showed up and escorted the pilots' vehicle out of the gate without incident, McIntyre said.

McIntyre, 48, began in 1996 as an apprentice for the river pilots, who now number about 45. She said she hadn't experienced threats or intimidation before.